# Genome-Wide Association Study of Fruit Traits Using 109 Germplasm Accessions of Camellia oleifera

## TL;DR

This study identifies genetic markers linked to fruit traits in Camellia oleifera, offering insights for breeding better oil-producing trees.

## Contribution

The study reports 157 genetic loci and 110 candidate genes associated with fruit traits in Camellia oleifera, providing new molecular markers for breeding.

## Key findings

- 157 significant genetic loci were identified through genome-wide association analysis.
- 110 candidate genes were found to be associated with reproduction, development, and metabolism.
- Twenty-three genes were linked to metabolic pathways like terpenoids and polyketides.

## Abstract

Camellia oleifera is an important woody oil tree species in China. Understanding the genetic basis of its fruit traits is crucial for breeding improved varieties. In this study, we analyzed 109 C. oleifera accessions and identified 157 genetic loci associated with ten fruit traits. We found 110 candidate genes involved in reproduction, development, and metabolism. These findings provide valuable molecular markers for future breeding programs and contribute to our understanding of fruit development in woody plants.

Camellia oleifera Abel, recognized as a woody oil-producing tree species, possesses considerable economic significance. To improve the breeding efficiency of C. oleifera, it is crucial to elucidate the genetic foundation underlying the mechanisms regulating fruit traits. In this study, a total of 6,252,197 high-quality single-nucleotide polymorphisms (SNPs) were identified from 109 germplasm accessions. Through genetic structure analysis, these accessions were categorized into two distinct populations. The average fixation index (Fst) was found to be 0.0153, indicating weak population differentiation. The genome-wide association analysis (GWAS) identified 157 significant loci. From these loci, 110 candidate genes were selected, which were associated with disease resistance, reproduction, development, and RNA biosynthesis. Twenty-three genes were involved in metabolic pathways, including genetic information-processing protein families, metabolic protein families, terpenoids, and polyketides. The identification of gene loci closely related to fruit traits not only provides genetic data for studying the molecular mechanisms of fruit traits but also offers new research avenues for molecular breeding of C. oleifera.